Surgical drainage tube

ABSTRACT

In catheterization procedures using drainage tubing of uniform bore, the drainage of fluid is often in the form of a solid column of fluid which creates a vacuum in its wake, resulting in lesions in the bladder wall where wall tissue is drawn into the catheter drainage eyelet. This vacuum is greatly reduced if the drainage tube is provided with alternate zones of wide and narrow inside diameter wherein the wide zones are above the critical diameter which will support an unbroken column of fluid.

United States Patent McWhorter [151 3,683,930 l Aug. 15, 1972 2,749,9136/1956 Wallace 128/295 [54] SURGICAL DRAINAGE TUBE 72 Inventor: DanielM. McWhorter, 432 Phelps, ggigg g 3x32? fg 22 i Oct. 28, 70 FOREIGNPATENTS OR APPLICATIONS [2 App]. 4 5 666,090 7/1963 Canada ..l28/350 RRelated US. Application Data Primary Examiner-Dalton L. Truluck [63]Continuation-impart of Ser. No. 758,423, Sept. Attorney-John Ryan 9,1968, abandoned. [57] ABSTRACT 52 us. (:1. 128/349 R, 128/295 InCatheterization Procedures using drainage tubing of 51 1 Int. Cl. ..A6lm25/00 uniform bore, the drainage of fluid is often in the form 53 Fieldf Search 12 3 3 349 R, 5 R, 7 of a solid column of fluid which creates avacuum in 273 123 351 295; 138/121, 122 its wake, resulting in lesionsin the bladder wall where wall tissue is drawn into the catheterdrainage eyelet. 5 References Cited This vacuum is greatly reduced ifthe drainage tube is provided with alternate zones of wide and narrowin- UNITED STATES PATENTS side diameter wherein the wide zones are abovethe 2 622 623 2/1952 Michaudet 138/122 critical diameter which willsupport an unbroken 3,044,497 7/1962 Rebut ..13s/121 column 3 Claims, 3Drawing Figures CONVENTIONAL URINARY CATHETER f lO CONVENTIONAL URlNCOLLECTION Patemed Aug. 15, 1972 FIG.!

MANOMETER /COLLECT|ON BAG FIG. 3

SURGICAL DRAINAGE TUBE This application is a continuation-in-part of mycopending application Serial No. 758,423, filed September 9, 1968 nowabandoned.

This invention relates to drainage tubes used for transferring urinefrom a catheter to a drainage bag or storage vessel. More particularlyit relates to a drainage tube of an improved design which discouragesthe formation of a solid column of urine in the lumen of the tube.

Recognition of the danger of introducing infectious organisms by urinarydrainage systems which are open to the air has led to variousmodifications of a closed technique wherein a catheter has attached toits proximal portion a convenient length of clear plastic tubing whichterminates in a so-called drip chamber attached to the side wall of adrainage bag. Efforts are made to prevent the entry of air into thedrainage tubing and the catheter.

When fluid 'is drained from the body, however, it frequently fills theentire lumen of the drainage tube in a broken or unbroken column. Thedescent of such a column of fluid through the drainage tube by gravityflow creates a negative pressure or vacuum in the wake of the flow, andthis vacuum is transmitted back through the catheter to the distalportion thereof. This frequently results in a portion of the bladderwall being drawn into the eyelet in the catheter tip, under suction,with consequent irritation or even the formation of a le sion subject toinvasion by infectious organisms.

Recognition of this deficiency has led to various proposals for theintroduction of filtered air into the system. Such devices, however,while effective, are in tricate and expensive to manufacture. It is alsoknown to provide drainage tubes which are provided with a multiplicityof inwardly and outwardly extending corrugations, for the purpose of.preventing kinking of the tube. Such tubes are longitudinallyextensible, and are made by an expensive mold-blowing process whichlimits their production to short pieces.

It is withimprovements in such systems that the present invention isconcerned. It is a primary objective of this invention to provide adrainage tube which will minimize the formation of a solid column offluid descending by gravity through said tube. It is a further object ofthe invention to provide a drainage tube which will minimize thenegative pressure formed in the normal operation of a catheter-drainagetubedrainage vessel system. It is an additional object of this inventionto provide a drainage tube which minimizes the need for a drip tubefixed to a drainage bag.

The customary drainage tube used to conduct fluid from the proximal endof the catheter to the drainage vessel is a straight-walled flexibletransparent plastic tubing, conventionally of about three-eighths inchoutside diameter with walls about one thirty second of an inch thick. Ithas been found that if the normally uniform bore of a plastic drainagetube is converted to a bore or lumen having a periodically variablediameter with the maximum diameter of the lumen above the criticaldiameter of a tube which will support an un broken column of fluid, theformation of a solid column or plug of descending fluid is minimized oreven eliminated, with consequent reduction in the air aspirateddownwardly through the system and a reduction in the vacuum created inthe wake of the advancing fluid. Also a considerable increase in thelateral flexibility and manipulatability of the tube is achieved,compared with a'tube of uniform diameter at or above the criticaldiameter, the term critical diameter here referring to the maximumdiameter above which a given tube will no longer support an unbrokencolumn of a given volume of fluid. The tube is resistant to longitudinalextension, and has the further advantage of being extrudable incontinuous lengths, providing an economy of manufacture which makestheir one-time use feasible.

The invention will be more clearly understood with reference to thefollowing description and drawings, in which:

FIG. 1 represents a preferred embodiment of the invention, partiallybroken away, and enlarged.

FIG. 2 represents a test method for measuring the vacuum-inducingpotential of a drainage tube.

FIG. 3 represents, partly broken away, the drainage tube of thisinvention attached to :a conventional urinary catheter at the distal endand terminating in a conventional urine collection bag at its proximalend.

Referring to FIG. 1, a segment of a drainage tube 10 is shown, fittedwith a conventional adapter 12 for insertion into catheters of varyingsizes. The side walls of the drainage tube are not straight and ofuniform diameter, but are convoluted into a spaced-apart series ofstraight-walled sections 18 each separated from the succeedingstraight-walled section by a bulbous enlargement 19, which may besubstantially spherical or ovalshaped. The tube is thus divided into aset of alternating straight-walled chambers of minimum diameter 16 andcurved-walled chambers of maximum diameter 14. Such a formation, it hasbeen found, is conducive to breaking'up the tendency of draining fluidto form a cylindrical plug or broken series of plugs reaching from innerwall to inner wall, as in conventional smooth bore tubing.

In the employment of conventional smooth-bore drainage tubes, thepassage of fluid through the tube has been found to create vacuumreadings as high as millimeters of mercury, the average vacuum being 30to 40 millimeters in the lengths of tubing conventionally employed tospan the distance from catheter to collection bag. It is desirable thatsuch a vacuum be reduced by 50 percent or more, preferably to a level ofl5-20 millimeters of mercury or less.

For this purpose, it is desirable that the length of the bulbous sectionbe no .less than the length of the straight-walled section (Y and X ofFIG. 1, respectively). Expressed differently, in the drainage tubes ofthis invention the summation of the lengths of the straightwalledsegments of the tube should not exceed 50 percent of the total length ofthe tube. In FIG. 1, the length Y of the bulbous portions isapproximately four times the length X of the straight-walled sections,so that the summation of straight-walled sections constitutes 20 1percent of the total length of the tube.

To test the efficiency of a tube of this design, the test depicted inFIG. 2 was employed. A conventional smooth-bore drainage tube 20 wasconnected by a sidearm 22 to a vacuum recording device 24 such as amercury manometer. When a quantity of fluid was poured into the upperend of the tube 20 and allowed to flow through the tube by gravity,vacuum readings of around 50 millimeters of mercury were developed inthe manometer. When the smooth-bore tube was replaced by the variablebore tube of FIG. 1, repetition of the test gave vacuum readings of 20millimeters of mercury or less, or an average reduction of 60 percent inthe strength of the vacuum developed in the wake of the descendingfluid.

In general, it has been found that drainage tubes of this inventionfunction optimally when the inside diameter of the tube tube at itsenlarged or widest point is at least 0.250 inches, and when thisdiameter is at least percent greater than the minimum inside diameter ofthe tube. In such constructions, substantial reduction of 50 percent ormore in the vacuum developed during drainage may be achieved. To someextent this will depend on the frequency and the sharpness of thechanges in diameter of the lumen of the tube, but in general it ispreferred that for simplicity in manufacture the lumen of the tube havea diameter in selected regions which is between 25 percent and 100percent greater than the diameter in selected other regions.

It is customary in closed catheterization systems to provide a so-calleddrip chamber, customarily attached to the wall of the collection bag.Its function is to provide a break in the continuous stream of urine,thus discouraging the retrograde growth of bacteria. Drainage tubes ofthis invention, by providing what may be considered as a series of dripchambers within the tube itself, minimize or obviate the need forconventional drip chambers attached to the collection bag.

Having thus described my invention, I claim: claim:

1. In a drainage system for the catheterized drainage of urine bygravity flow, comprising a urinary catheter and a urine collectionvessel, that improvement which comprises a laterally flexible length ofplastic tubing attached to the proximal end of said catheter the wallsof said plastic tubing comprising a set of axially spaced-apartstraight-walled sections,

said straight-walled sections alternating with sections in which thewalls of said plastic tubing are expanded in bulbous form,

the lumen of said plastic tubing thereby varying in I diameter along itslength,

and the proximal end of said plastic tubing terminating in said urinecollection vessel.

2. The system according to claim 1 in which the summation of the lengthsof the straight-walled segments does not exceed 50 percent of thetotal'length of the tube.

3. The system according to claim 1 wherein the maximum inside diameterof the plastic tubing is between 25 percent and I00 percent greater thanthe minimum inside diameter of said tubing, said maximum inside diameterbeing at least 0.250 inches.

1. In a drainage system for the catheterized drainage of urine bygravity flow, comprising a urinary catheter and a urine collectionvessel, that improvement which comprises a laterally flexible length ofplastic tubing attached to the proximal end of said catheter the wallsof said plastic tubing comprising a set of axially spaced-apartstraight-walled sections, said straight-walled sections alternating withsections in which the walls of said plastic tubing are expanded inbulbous form, the lumen of said plastic tubing thereby varying indiameter along its length, and the proximal end of said plastic tubingterminating in said urine collection vessel.
 2. The system according toclaim 1 in which the summation of the lengths of the straight-walledsegments does not exceed 50 percent of the total length of the tube. 3.The system according to claim 1 wherein the maximum inside diameter ofthe plastic tubing is between 25 percent and 100 percent greater thanthe minimum inside diameter of said tubing, said maximum inside diameterbeing at least 0.250 inches.